/*
 * Copyright (c) 2011-2012 Alexander Dubu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * o  Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * o  Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * o  Neither the name Axil nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package axil.stdlib.text.type;

import axil.api.AxilObject;
import axil.framework.type.Added;
import axil.framework.type.Concatenated;
import axil.framework.type.Sized;
import axil.stdlib.collection.type.Sequence;
import axil.stdlib.core.type.Atom;


/**
 * The base type for all character-oriented types, such as character and
 * string.
 */
public abstract class Text extends Atom
	implements Sequence<Char>, Iterable<Char>, Sized, Concatenated, Added
{
	/**
	 * Tell if this collection is empty. Use of this method is much preferred
	 * over the idiom 'size() == 0' since determination of size may not be a
	 * constant time operation.
	 */
	public boolean empty() {
		return size() == 0;
	}


	/**
	 * Get the character at the given index (from zero). If the index is outside
	 * of the range of the object, then an exception is thrown.
	 */
	public abstract char ch(int index);


	/**
	 * Concatenate the given object onto this object, returning a new object.
	 * Neither this object nor the given object are altered. The given object
	 * is never null or nil, but may not be an object of the expected type.
	 */
	public AxilObject concatenate(AxilObject other)	{
		return this.add(other);
	}
}
